by Lindsay H. Jones, USA TODAY Sports

by Lindsay H. Jones, USA TODAY Sports

OXNARD, Calif. â?? Stern warning from both coaching staffs, extra police officers, many of them wearing flak jackets, police dogs and the decision to separate Cowboys and Raiders fans to opposite sides of the training facility couldn't prevent a melee in the first of two joint practices Tuesday afternoon.

A brawl between the Raiders offense and Cowboys defense â?? started after a hard tackle by Dallas cornerback Morris Claiborne â?? spilled over the sideline and up against the fence where a large group of Raiders fans were watching.

That's when it got ugly.

Dallas cornerback B.W. Webb said he felt someone on his back, swinging a helmet at his head. Thinking it was a player, Webb spun around and swung his right arm. Webb told USA TODAY Sports he didn't know it was a fan. Many of the Raiders fans brought helmets to get autographed by players after the practice.

"That's definitely a dangerous situation," Webb said. "I don't know why fans would want to jump on this side of the fence. I don't think they'd like it too much on this side."

After that fight dissipated, police officers moved to stand between the sideline and the Raiders fan section.

Raiders fans, many of whom arrived hours before the practice began, were far louder and more spirited than their Cowboys fans counterparts, though both sides did engage in several rounds of "Cowboys Suck" and "Raiders Suck" chants. The chants reached their peak after the big brawl near the Raiders' section.

It didn't seem to bother either Cowboys owner Jerry Jones nor Oakland owner Mark Davis, who held a joint media session after the practice. There, they both laughed about the scrums.

"I would have at least expected [Davis] to go over there and shut that group down," Jones said, laughing. "I don't know what was holding him back."

Davis interjected that he just wanted his players to keep their helmets on.

"You're supposed to be the host here, you go shut them up," Davis said.

Jones even lauded one of Oakland's players (offensive linemen Austin Howard) for his feistiness against the Cowboys players. Howard was involved in at least one scuffle.

"No. 77 is a tough guy. Got one of the most effective uppercuts I've seen in football," Jones said. "Boy, that 77 was putting some hurt on 'em."